Sierra Negra volcano, Galápagos: my 2009 ride and hike on Isabela

In early June 2009, a month into my trip through South America, I spent a day on Sierra Negra, the large shield volcano on Isla Isabela in the Galápagos. We went up partly on horseback and partly on foot, to the edge of a caldera so wide the photographs never do it justice. I wrote about it on 9 June.

This page retells that day for 2026, with context the 22-year-old me did not have. It is a memory of one visit, not a current guide; arrangements on the islands are set by the national park and change over time.

Where Sierra Negra is

Isabela is the largest of the Galápagos islands, and Sierra Negra sits at its southern end, above the small town of Puerto Villamil. It is one of the most active volcanoes in the archipelago. In my diary I noted it had erupted in 2005 and described it as around 10km across. It has erupted again since my visit, most recently in 2018, which is a reminder that any account of the trail, including mine, can go out of date.

My route to the islands went Quito, then Santa Cruz, Isabela and Floreana, before heading back to the mainland at Guayaquil.

Getting up: horses, then feet

We reached the site by horseback and walking. The horses set a slow pace, and the real challenge was the heat rather than the ride. By the end of the day I had picked up a mild sunburn, which I had managed to avoid for the previous month. My description of myself slumped on a horse in grandad socks and a stained T-shirt was not flattering.

The caldera

Then the rim. "Man. It was huge, you can't really tell here can you?" was the best I managed in writing. It is one of the largest volcanic calderas in the world, and standing on the edge of it is the kind of sight that makes your own scale obvious.

Walking on volcanic ground

Beyond the rim the walk crossed old lava and ash fields. Two details stayed with me. The rock was ashen and crumbled under my feet "like chalk", and cactuses taller than me grew straight out of what I called "these fiery plains". I had never walked on ground that was volcanically active, and I wrote, honestly, "neither had I until this day".

It is a different kind of walking from a trail at home: uneven, sharp in places, hot, and with little shade. Good footwear, sun protection and plenty of water matter more than fitness.

What I would tell someone planning it now

• Go with an authorised guide. Visits within the Galápagos National Park are regulated; check current rules on guides and routes.
• Check current access. Trails close or change during volcanic activity.
• Take sun and water seriously. The highlands can be misty at the start and very hot later.
• Wear proper shoes. Volcanic rock is unforgiving.
• Read current travel advice for Ecuador, such as the UK Foreign Office page.

The rest of the trip

A few weeks after Isabela, I was cycling down towards Santa Teresa on the back route to Machu Picchu, then in July down Bolivia's Death Road. The whole 2009–2011 chapter is gathered on adventure travel, alongside the marathon I was supposedly training for: training on the road.

Questions readers ask

How did you get to Sierra Negra?

By horseback and on foot, with a guide, in June 2009.

How big is the Sierra Negra caldera?

I recorded it as around 10km across in 2009. It is one of the largest calderas in the world.

Is Sierra Negra still active?

Yes. It has erupted since my visit, including in 2018, so check current park access before planning a hike.

Sources and notes

• My 2009 South America route
• Original 2009 diary: Galapagos… and Sierra Negra, 9 June 2009
• UK Foreign Office travel advice: Ecuador

Photographs are my own from June 2009. Diary quotations are from my original entry dated 9 June 2009.

Written in October 2026 from my own contemporaneous records.